Enteral feeding by applying a percutaneous endoscopic gastrostomy (PEG) is methodically safe and clinically established (Dormann, A. J., et al. Am J Gastroenterol 1999).
Moreover, so-called button systems are known, which are protected against slipping out by means of a balloon or a flexible sleeve. After introducing the probe tube of such a button system through the stoma into the stomach, the balloon is filled from outside via a valve with a liquid, or the sleeve is relieved. During filling, the balloon expands or the sleeve deploys its final shape. The thereby formed retaining member fixes the system at the distal end. The button system is thereby supported by a holding part outside on the abdominal wall. Usually, water is used as the liquid for deploying the balloon.
In the known anterior balloon-button systems, the probe tube is surrounded by an outer tube resting against it at the outside. The outer tube is joined to the probe tube, e.g. bonded by adhesive, both on its distal and proximal end. If water or the like is then introduced into the interspace between the outer tube and the probe tube (to be more precise, between the inner surface area of the outer tube and the outer surface area of the probe tube), the outer tube will assume a balloon-like shape. In order to enable this, the outer tube must be made of a material having a sufficiently high degree of flexibility, e.g. of silicone.
The weak points of this known balloon-button system are the connection points or bonding locations between the outer tube and the probe tube, which forms the inner tube in that section where it is surrounded by the outer tube. These connection or seam locations turned out not to support a permanent load so that water from the balloon could reach the stomach, and the safe fit of the system could no longer be guaranteed.
In order to encounter the described drawback, balloon-button systems have been developed, wherein the probe tube and the outer tube are manufactured in one piece. Such a tube is obtained in that the distal end of the probe tube is turned inside out and is returned or pulled up over the distal end of the then resulting inner tube. In this manner, the distal connection of the inner tube and the outer tube can be formed in one piece. However, the outer tube, now as before, must be connected at its proximal end to the inner tube by bonding or the like.
These systems are insofar disadvantageous as the inner tube and the outer tube, due to their one-piece configuration, must be manufactured from the same material. In other words, the inner tube and the outer tube have the same flexibility. It has turned out to be difficult to use a kind of mean flexibility so that, on the one hand, the outer tube is sufficiently flexible to form a balloon, and the inner tube, on the other hand, has sufficient and required stability. This applies even then when the wall thickness of the probe tube varies along its axial length.
Button systems are already known wherein the balloon is comprised of differently configured retaining members, e.g. sleeves. In this respect, reference is made to EP-A-0 824 929 and the therein mentioned documents U.S. Pat. No. 3,108,595 and U.S. Pat. No. 4,666,433.